"The only cloud we could use from the commercial
sector, at the time we were architecting the system, was Amazon's
AWS. Thus we decided to build an AWS work-alike for the
Universities participating in VGrADS, do the vgES port to AWS, and
then to run the application on the TeraGrid, Amazon AWS, and the
various University machines while they were emulating the AWS
cloud. Eucalyptus was the infrastructure we built to support the
effort at the University sites.
"Because we couldn't change AWS and we didn't have the resources
to specialise vgES for more than one cloud API, the quality of the
AWS mimicry had to be pretty high. Our goal was to have vgES run in
exactly the same manner on AWS and the other Eucalyptus clouds
without modification or special purpose code for either."